Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

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The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

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Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in PYTHON3):

Solution:
import sys

def main():
    n,m=list(map(int,sys.stdin.readline().split()))
    
    field=[]
    
    for i in range(n):
        row=list(map(int,sys.stdin.readline().split()))
        field.append(row)
    
    nmoves=0
    moves=[]
    
    while True:
        minrow=[min(field[i][j] for j in range(m)) for i in range(n)]
        mincol=[min(field[i][j] for i in range(n)) for j in range(m)]
        maxrow,imaxrow=max((item,index) for index,item in enumerate(minrow))
        maxcol,imaxcol=max((item,index) for index,item in enumerate(mincol))
        if maxrow==maxcol==0: break
        
        if (n>=m and maxcol>0) or (maxrow==0):
            moves.append((maxcol,-(imaxcol+1)))
            nmoves+=maxcol
            for i in range(n):
                field[i][imaxcol]-=maxcol
        elif maxrow>0:
            moves.append((maxrow,imaxrow+1))
            nmoves+=maxrow
            for j in range(m):
                field[imaxrow][j]-=maxrow
        
    maxelem=max(field[i][j] for i in range(n) for j in range(m))
    if maxelem>0: 
        sys.stdout.write('-1'+'\n')
        return
    
    sys.stdout.write(str(nmoves)+'\n')
    for repeat,move in moves:
        for _ in range(repeat):
            mtype='row' if move>0 else 'col'
            sys.stdout.write(mtype+' '+str(abs(move))+'\n')
    
main()